There are a number of Scripture passages that identify the flood waters with the present-day seas (Amos 9:6 and Job 38:8-11 note “waves”). If the waters are still here, why are the highest mountains not still covered with water, as they wer...e in Noah's day? Psalm 104 suggests an answer. After the waters covered the mountains (verse 6), God rebuked them and they fled (verse 7); the mountains rose, the valleys sank down (verse 8) and God set a boundary so that they will never again cover the earth (verse 9)[1]. They are the same waters!

Isaiah gives this same statement that the waters of Noah would never again cover the earth (Isaiah 54:9). Clearly, what the Bible is telling us is that God acted to alter the earth's topography. New continental landmasses bearing new mountain chains of folded rock strata were uplifted from below the globe-encircling waters that had eroded and leveled the pre-Flood topography, while large deep ocean basin were formed to receive and accommodate the Flood waters that then drained off the emerging continents.

That is why the oceans are so deep, and why there are folded mountain ranges. Indeed, if the entire earth's surface were leveled by smoothing out the topography of not only the land surface but also the rock surface on the ocean floor, the waters of the ocean would cover the earth's surface to a depth of 1.7 miles (2.7 kilometers). We need to remember that nearly 70 percent of the earth's surface is still covered by water. Quite clearly, then, the waters of Noah's Flood are in today's ocean basins.

Of course the whole world flooded. It's just that the "whole world" was only a few square miles for most people back when the story was written, which, when you consider that, makes a story about the "whole world" flooding seem much more plausible.

And all of these mountains rising, valleys falling, and waters fleeing left absolutely no geological traces of having done so! Why? Well, because God covered up the evidence, making it appear that Earth is billions of years old and that there never has been a worldwide flood. And why would God do that, you may ask. Why, to test our faith in him, of course.

A hilariously desperate attempt to reconcile the Biblical account with the facts. The facts are stretched, sawed, and forced into the conclusion prepared for them.
You're not supposed to start out with a conclusion and bend the evidence to fit it. You're doing it wrong.